The present invention relates to an apparatus to cut out the vent of a bird which is suspended from a hook of a conveyor, having at least one rotatingly driven hollow cylindrical knife which is secured to a slide which is reciprocal along a guide in the direction of the bird. A vacuum can be generated in the knife, and the slide is provided with a follower which engages a curved cam of the apparatus. Means are provided to bring the bird's vent in the correct position opposite the knife.
Such apparatuses have been known in many configurations and in practice they are mostly part of a series of processing apparatuses for birds such as hens, chickens and the like being prepared for consumption which being disposed as much as possible along the same conveyor.
It is a general problem to form a vent cutting apparatus for birds with varying leg lengths and other dimensions related to growth, which will bring the birds to correct positions opposite the cylindrical knives, make a round incision to the correct depth around the vent of the bird without damaging the tail, and bring out of the bird the cut-out back and a connected part of the intestines.
It appeared almost impossible to achieve all this with an apparatus in which the slides and their followers follow a fixed curved path under all circumstances.
The present invention tends to improve an apparatus of the above described type so that the noticed problems are abolished. When doing so, one started from the fact that it is impossible to have the slides always follow a fixed curved path.
According to the invention, the followers of the slides, at the location where the vent is cut out, have a backlash of a few centimeters relative to the curved path of the cam, said backlash being removed by a stop of the slide which cooperates with means to bring the bird's vent in the correct position opposite the knife. The means for bringing the bird's vent to a correct position opposite the knife includes positioning means which can be moved up and down along the guides, said positioning means also having a follower which engages a curved cam surface.
As mentioned above, measures should also be taken to prevent the tail, which is not of the same size for all birds, from being damaged by the cylindrical knife. This is realized in the first place by providing the positioning means with a clip which keeps the bird's tail away from the rotating knife, said clip being brought in the correct position by a curved cam surface. The clip is preferably provided with slot holes, serving as a bearing for a roll with a tapered central portion which, when bringing the tail in the correct position, rolls along said tail.
Moreover, each of the cylindrical knives is arranged around a non-rotating vacuum pipe which, preliminary to the severing of operation, sucks the back somewhat upwardly.
The apparatus can also be provided with so-called clip hands which are biased by an elastic compressing member which is able to adapt itself to the differences in circumference of the birds. Said elastic compressing member consists of a belt or string, passed along three pulleys, one of which is biased by a spring. The bars on which the clip hands are placed are rotated by the belt or string such that, during the time the bird is processed with the rotating knife, it is forced against the positioning member.
Passing the rotatingly driven hollow cylindrical knives as close along the back as possible is a problem which requires special attention. If the knife is not adapted to pass closely along the back, then the egg glands of the birds may be damaged and this leads to inadmissible contamination. In many, but not in all, cases the correct position is achieved by so-called clip hands, also provided in the apparatus. If, however, the birds are not suspended from the legs, as is usual in Europe, but from the inwardly directed knees, as is usual in the USA, the clip hands are not sufficient because the force with which they press against the birds should not be increased too much. The invention also tends to improve this and, for some embodiments, even makes the clip hands superfluous.
According to the invention, this is achieved by having the chest clip extend in a downwardly inclined manner in an outward direction.
If the birds are suspended from the hooks of the conveyor with the knees directed outwardly, the downward extension of the chest clip, in side view, is at least partially in the configuration of a circle section.
If clip hands are present then the chest clip has straight portions which, in side view, extend downwardly and outwardly at an angle, said angle being preferably approximately 30.degree..
The invention will be further elucidated hereinafter on the basis of the drawing, in which by way of example an embodiment is shown of an apparatus according to the invention.